It is generally known that platinum catalysts will accelerate the addition of compounds containing silicon-bonded hydrogen atcms to compounds containing aliphatic unsaturation. Oftentimes, it is desirable to mix the platinum catalysts with the compounds containing silicon-bonded hydrogen atoms and the compounds containing aliphatic unsaturation and carry out the addition reaction at some future time. Unfortunately, such mixtures of silicone compounds and platinum catalysts do not have sufficient shelf life or stability to remain unchanged at ambient temperature (20.degree. to 30.degree.) for sufficient periods of time to permit their use in some applications.
Organopolysiloxane compositions which contain compounds that inhibit crosslinking are described in, for example, U.S. Pat. No. 3,192,181 to Moore, in which the ccmposition contains an organosilicon compound having an average of at least two monovalent radicals containing aliphatic unsaturation per molecule, an organosilicon compound having an average of at least two silicon-bonded hydrogen atoms per molecule, a platinum catalyst and benzotriazole as an inhibitor.
Heat curable organopolysiloxane compositions are described in U.S. Pat. No. 3,992,355 to Itoh et al in which the compositions contain a diorganopolysiloxane having an average of at least two vinyl groups per molecule, an organohydrogenpolysiloxane having at least two SiH groups per molecule, a platinum catalyst and a hydrazine compound to inhibit crosslinking.
It is, therefore, an object of the present invention to provide an organopolysiloxane ccmposition having improved storage stability. Another object of the present invention is to provide an organopolysiloxane composition having improved "working times". Still another object of the present invention is to provide an organopolysiloxane composition having improved cure rates at elevated temperatures. Still another object of the present invention is to provide an inhibited catalyst for the hydrosilation of vinyl siloxanes. A still further object of the present invention is to provide a heat-curable organopolysiloxane composition having improved storage stability and "pot-life".